Fruit moves fastest and green leaves. Meat, cheese, oil and fats slowest.

But we often eat combinations: and the slowest component of your food determines the speed of the whole.

Also: it's a one lane road and "over taking" is not possible.

So, eating a fast moving meal after a slow moving meal results in the fast mover getting stuck behind the slow mover.

Hence I start my day without and slow food (only fruit, herbs, green leaves, spices, ginger => usually a smoothy); and end the day with slow food (oily food, nuts, seeds, beans; usually combined with green leaves as we need a lot green leaves).

YMMV

The goal is more than 13 plants a day and your movement will be very consistent

The study. It basically says that this is something one perhaps should consider in clinical settings and that the speed of fecal matter might be a worthwhile direction for future inquiry.

"Altogether, a better understanding of the complex, bidirectional interactions between the gut microbiota and transit time is required to better understand gut microbiome variations in health and disease."

It does not say 'this is a sign of health and that is not'.

You gotta lay down a fermentation base.